(1) Field of the Invention
This invention relates to an antechamber system Diesel engine and more specifically to a Diesel engine having a diesel engine combustion chamber-type combustion chamber.
(2) Description of the Prior Art
The antechamber system of the conventional Diesel engine is classified into two types, one being a precombustion chamber type and the other being a swirl chamber type. The precombustion type includes a combustion chamber consisting of a front chamber and a rear chamber having the same axis with each other inside a cylinder head, a communication port communicating the antechamber with a main combustion chamber defined in a piston, and a glow plug and a fuel injection nozzle each disposed in such a manner as to face the rear chamber. However, the conventional combustion chamber is formed by superposing two blocks one upon another via a packing between them, i.e., a block being provided with the latter half of the rear chamber and the other being provided with the former half of the rear chamber, the front chamber having its one end opening to the former half of the rear chamber and the communication port communicating the front chamber with the main combustion chamber formed in the piston. For this reason, the number of man-hours for the production of the combustion chamber is large and the production cost of the combustion chamber is high. In addition, the combustion chamber is not free from the drawbacks in that gas leak is apt to occur from the seam portion of the two blocks. Furthermore, when the tip portion of the glow plug is allowed to protrude into the rear chamber through the cylinder head and through the block provided with the latter half of the rear chamber, gas leak tends to occur from the penetrating portion of the glow plug and also from the seam between the block and the cylinder head. Hence, the gas seal method becomes complicated and difficult.
On the other hand, in the swirl type combustion chamber, since the most parts of the combustion chamber are integrally formed with the cylinder head, there occurs a problem as to the mixing of the fuel and the air because the combustion chamber is defined by a single chamber, although this type is free from the above-mentioned problem of the fitting of the glow plug. In other words, although mixing of the air with the combustion fuel spray is effected by means of the swirl of vortex flow generated inside the antechamber by compression due to the piston, auxiliary mixing of the air with the fuel spray is not effected due to minute turbulence of the flow inside the combustion chamber. Hence, this type involves the problem that occurrence of the exhaust gas smoke becomes greater than the above-mentioned precombustion chamber type.